Hi, Ernie and welcome to the forum.
I have had a few Sankyos before and was impressed with their quality. This model uses an EFM halogen lamp. Looks like these are readily available on Ebay for $5.00 and up:
http://www.ebay.com/sch/i.html?_nkw=efm ... &_from=R40I'm sure someone will chime in with more info about their experience with these projectors. in the meantime here are som specs I found:
Sankyo Sound 500marketed in 1976-77
super 8 mm film
lens: Sankyo Zoom f: 1.4 \ F: 15-25 mm
lamp: 50 W, 8 V, EFM
reel capacity: 180 m
projection: forward, reverse
projection speed: 18, 24 fps, by selector switch
film loading: automatic threading
sound: magnetic playback on main sound track
sound mode: mono
sound control: volume, double rec
amplfier: 2 ICs, 5 Silicon transistors, 5 Silicon diodes
amplifier output: 4 W (6 Ohm)
frequency response: ?
sound recording: magnetic recording on main track
sound-on-sound: and sound fading
recording level control: auto (ALC)
input terminal: Microphone, Phono, DIN
input jacks: Mic, Phono: 3.5 mm diameter jack; DIN: 5-pin DIN (European type)
output terminal: Monitor, Line-out, DIN, External Speaker
output jacks: Monitor, Line-out: 3.5 mm diameter jack; DIN: 5-pin DIN (European type); Ext Sp: 6.5 mm diameter jack
built-in speaker: 4" diameter round speaker, 2 W (8 Ohm)
motor: ellectronically controled DC magnetic motor
power source: 100-110-117-125-200-240 V AC, 50/60 Hz, 130 W
weight: 8300 g
dimensions: 190 x 224 x 324 mm
made in Japan by Sankyo
presented at Photokina 1976